The internal fixation of bone fragments through the utilization of bone screws is well known. The screws may be manufactured from metal, but metal screws may need to be removed after the fragments have knitted. Absorbable materials have recently been developed for various medical applications, including for the fixation of bone fragments. Absorbable materials avoid the need for removal of the bone screw at a subsequent date, thereby eliminating the need for additional surgery.
Because the bone screw is screwed into the fragments in order to fix them, there is a need for a tool which rotates the screw about its longitudinal axis. Placement of the bone screw may require great accuracy, and various devices have been proposed for fixing a bone screw relative to its cooperating driver. Absorbable bone screws, however, generally are formed from materials not having the strength characteristics of metal, so that prior surgical screwdrivers may not maintain proper orientation of the screw relative to the driver. The absorbable screw may, for example, become cocked or knocked off axis during insertion, with the result that the screw may not be properly inserted. In addition, the surgeon may not have a clear view of the screw during the entire installation process, because the view may be blocked by tissue, blood or the like, so as to be unaware that the screw has not been properly positioned.
In view of the above, those skilled in the art will understand that there is a need for an absorbable bone screw and a tool for its insertion which assure proper positioning of the screw relative to the driver at all times. The disclosed invention is thus directed to a unique absorbable bone screw, and a tool especially adapted for insertion of that bone screw.